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One-step synthesis of thermally stable artificial multienzyme cascade system for efficient enzymatic electrochemical detection

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Nano Research 2019年第12期12卷 3031-3036页

作者： Xiqing Cheng Jinhong Zhou Jiayu Chen Zhaoxiong Xie Qin Kuang Lansun Zheng State Key Laboratory of Physical Chemistry of Solid Surfaces Collaborative Innovation Center of Chemistry for Energy Materialsand Department of ChemistryCollege of Chemistry and Chemical Engineering Xiamen UniversityXiamen 361005China Pen-Tung Sah Institute of Micro-Nano Science and Technology Xiamen UniversityXiamen 361005China

Recently,metal-organic framework(MOF)-based multienzyme systems integrating different functional natural enzymes and/or nanomaterial-basedartificial enzymes are attracting increasing attention due to their high catalytic efficiency and promising application in sensing.Simpleand controllable integration of enzymes or nanozymes within MOFs is crucial for achieving efficient cascade catalysis and high stability.Here,we report a facile electrochemical assisted biomimetic mineralization strategy to prepare an artificial multienzyme system for efficient electrochemicaldetection of biomolecules.By using the G0x@Cu-MOF/copper foam(G0x@Cu-MOF/CF)architecture as a proof of concept,efficientenzyme immobilization and cascade catalysis were achieved by in situ encapsulation of glucose oxidase(GOx)within MOFs layer grown onthree-dimensional(3D)porous conducting CF via a facile one-step electrochemical assisted biomimetic mineralization strategy.Due to thebio-electrocatalytic cascade reaction mechanism,this well-designed GOx@Cu-MOF modified electrode exhibited superior catalytic activityand thermal stability for glucose sensing.Notably,the activity of GOx@Cu-MOF/CF still remained at ca.80%after being incubated at 80℃.In sharp contrast,the activity of the unprotected electrode was reduced to the original 10%after the same treatment.The design strategypresented here may be useful in fabricating highly stable enzyme@MOF composites applied for efficient photothermal therapy and otherplatform under high temperature.

关键词： metal-organic frameworks artificial multienzyme electrochemical assisted biomimetic mineralization glucose detection thermal stability

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Methodology to develop machine learning algorithms to improve performance in gastrointestinal endoscopy

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World Journal of Gastroenterology 2018年第45期24卷 5057-5062页

作者： Thomas de Lange Pal Halvorsen Michael Riegler Department of Transplantation Oslo University HospitalOslo 0424Norway Institute of Clinical Medicine University of OsloOslo 0316Norway Center for Digital Engineering Simula Metropolitan Fornebu 1364Norway

assisted diagnosis using artificial intelligence has been a holy grail in medical research for many years, and recent developments in computer hardware have enabled the narrower area of machine learning to equip clinicians with potentially useful tools for computer assisted diagnosis(CAD) systems. However, training and assessing a computer's ability to diagnose like a human are complex tasks, and successful outcomes depend on various factors. We have focused our work on gastrointestinal(GI) endoscopy because it is a cornerstone for diagnosis and treatment of diseases of the GI tract. About 2.8 million luminal GI(esophageal, stomach, colorectal) cancers are detected globally every year, and although substantial technical improvements in endoscopes have been made over the last 10-15 years, a major limitation of endoscopic examinations remains operator variation. This translates into a substantial inter-observer variation in the detection and assessment of mucosal lesions, causing among other things an average polyp miss-rate of 20% in the colon and thus the subsequent development of a number of post-colonoscopy colorectal cancers. CAD systems might eliminate this variation and lead to more accurate diagnoses. In this editorial, we point out some of the current challenges in the development of efficient computer-based digital assistants. We give examples of proposed tools using various techniques, identify current challenges, and give suggestions for the development and assessment of future CAD systems.

关键词： Endoscopy Artificial intelligence Deep learning Computer assisted diagnosis Gastrointestinal

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Improvement on the performance of perovskite solar cells by doctor-blade coating under ambient condition with hole-transporting material optimization

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Journal of Energy Chemistry 2019年第11期28卷 207-213页

作者： Deng Wang Jiming Zheng Xingzhu Wang Jishu Gao Weiguang Kong Chun Cheng Baomin Xu Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055GuangdongChina Academy for Advanced Interdisciplinary Research Southern University of Science and TechnologyShenzhen 518055GuangdongChina School of Chemistry and Chemical Engineering Harbin Institute of TechnologyHarbin 150001HeilongjiangChina

Numerous fabrication methods have been developed for high-efficiency perovskite solar cells(PSCs). However, these are limited to spin-coating processes in a glove box and are yet to be commercialized. Therefore, there is a need to develop a controllable and scalable deposition technique that can be carried out under ambient conditions. Even though the doctor-blade coating technique has been widely used to prepare PSCs, it is yet to be applied to high-efficiency PSCs under ambient conditions(RH ~45%, RT ~25 °C). In this study, we conducted blade-coating fabrication of modified high-efficiency PSCs under such conditions. We controlled the substrate temperature to ensure phase transition of perovskite and added dimethyl sulfoxide(DMSO) to the perovskite precursor solution to delay crystallization, which can facilitate the formation of uniform perovskite films by doctor-blade coating. The as-prepared perovskite films had large crystal domains measuring up to 100 μm. Solar cells prepared from these films exhibited a current density that was enhanced from 17.22 to 19.98 m A/cm^2 and an efficiency that was increased from 10.98% to 13.83%. However, the open-circuit voltage was only 0.908 V, probably due to issues with the hole-transporting layer. Subsequently, we replaced poly(3,4-ethylenedioxythiophene) polystyrene sulfonate(PEDOT:PSS) with Ni O x as the hole-transporting material and then prepared higher-quality perovskite films by blade-coating under ambient conditions. The as-prepared perovskite films were preferably orientated and had large crystal domains measuring up to 200 μm;The open-circuit voltage of the resulting PSCs was enhanced from 0.908 to 1.123 V, while the efficiency increased from 13.83% to 15.34%.

关键词： Hole-transporting material NiOx Perovskite solar cells Thermally assisted blade-coating Ambient condition Fabrication

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Small intestinal hemolymphangioma treated with enteroscopic injection sclerotherapy: A case report and review of literature

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World Journal of Gastroenterology 2020年第13期26卷 1540-1545页

作者： Nian-Jun Xiao Shou-Bin Ning Teng Li Bai-Rong Li Tao Sun Department of Gastroenterology Air Force Medical CenterBeijing 100142China Department of Pathology Air Force Medical CenterBeijing 100142China

BACKGROUND Hemolymphangiomas are rare malformations composed of both lymphatic and vascular vessels and are located in the pancreas,spleen,mediastinum,etc.Small intestinal hemolymphangioma is extremely rare and often presents as obscure gastrointestinal bleeding.It is rarely diagnosed correctly before the operation.Endoscopic injection sclerotherapy is usually used as a management of bleeding in esophageal varices and was occasionally reported as a treatment of vascular malformation.The treatment of small intestinal hemolymphangioma with enteroscopic injection sclerotherapy has not been reported.CASE SUMMARY A 42-year-old male complained of recurrent episodes of melena and dizziness,fatigue and reduced exercise capacity for more than 2 mo.Gastroduodenoscopy and blood test revealed a gastric ulcer and anemia.Treatment with oral protonpump inhibitors and iron did not improve symptoms.We then performed a capsule endoscopy and anterograde balloon-assisted enteroscopy and revealed a hemolymphangioma.Considering it is a benign tumor without malignant potential,we performed enteroscopic injection sclerotherapy.He was discharged 4 days later.At follow-up 3 mo later,the melena disappeared.Balloon-assisted enteroscopy revealed an atrophied tumor atrophied and no bleeding.Argon plasma coagulation was applied to the surface of the hemolymphangioma to accelerated healing.When he returned for follow-up 1 year later,anemia was resolved and the tumor had been cured.CONCLUSION Balloon-assisted enteroscopy and capsule endoscopy are effective methods for diagnosis of hemolymphangioma.Enteroscopic injection sclerotherapy is an effective treatment.

关键词： Hemolymphangioma Lymphangioma Small intestinal tumor Balloon assisted enteroscopy Obscure gastrointestinal bleeding Enteroscopic injection sclerotherapy Case report

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Effects of Dielectric Barrier Discharge Plasma on the Combustion Performances of Reverse-Flow Combustor in an Aero-Engine

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Journal of Thermal Science 2019年第5期28卷 1035-1041页

作者： DENG Jun PENG Changxin HE Liming WANG Shuai YU Jinlu ZHAO Bingbing Science and Technology on Plasma Dynamics Laboratory Air Force Engineering University Xi'an 710038 China AECC Hunan Aviation Powerplant Research Institute Zhuzhou 412002 China

In order to apply plasma assisted combustion(PAC) into a reverse-flow aero-engine and verify the improvement of combustion performance, a feasible approach was proposed in this work. In this approach, based on the structure characteristics of the reverse-flow combustor, a parallel plate double dielectric barrier discharge(DBD) PAC actuator was designed to generate plasma. It was installed at the front of combustor. When the actuator is driven, the original air flow is not disturbed for the device’s structure and installation. Using aviation kerosene as fuel, the effects of plasma on ignition boundary and outlet temperature of the combustor were experimentally investigated at atmosphere pressures. Through the dual high voltage differential power supply, the large gap, large area and uniform plasma discharge was achieved. The results of PAC actuator discharge indicate that inlet air temperature has a small increase of 4–9 K. After PAC is applied, the combustion performances of reverse-flow combustor in an aero-engine are remarkably improved. Experimental results indicate that ignition boundary is widened by 3.7%–12.5% because of the impact of plasma. Outlet highest temperature of combustor is raised by 19–75 K;outlet temperature distribution coefficient is reduced by 11.1%–26.6%. This research provides an effective and practicable way to implement the application of PAC in aero-engine combustor and has some engineering application significance.

关键词： aero-engine reverse-flow combustor double dielectric barrier discharge plasma assisted combustion

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The effects of modulation period,modulation ratio,and deposition temperature on microstructure and mechanical properties of ZrB_2/W multilayers

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Science China(Technological Sciences) 2010年第9期53卷 2350-2354页

作者： LIU MengYin,TAN Ming,LIU GuangQing,WANG HaiYuan,XUE FengYing,DENG XiangYun & LI DeJun College of Physics and Electronic Information Science,Tianjin Normal University,Tianjin 300387,China College of Physics and Electronic Information Science Tianjin Normal University Tianjin China

Monolithic ZrB2,W coatings and ZrB2/W multilayers with different modulation periods and modulation ratios were synthesized by ion beam assisted deposition at room temperature and 400°C.X-ray diffraction (XRD),scanning electron microscopy (SEM),surface profiler,and nanoindention were employed to investigate the influences of the deposition temperature and the modulation period on the growth,textures,interface structure,and mechanical properties of the multilayers.The results indicated that the multilayer with modulation period of 13 nm synthesized at room temperature possessed a higher hardness of 23.8 GPa.Deposition temperature gave a significant contribution to mechanical property enhancement.The 400°C-deposition temperature led to a maximum hardness and elastic modulus value of 32.1 and 399.1 GPa for ZrB2/W multilayer with a modulation period of 6.7 nm.Its critical load increased to 42.8 mN and residual stress decreased to -0.7 GPa.A higher deposition temperature can cause an increase in interfacial atomic mixture and mobility of surface species,which induceds an increase in areal atomic density and dislocation pinning.These results as well as small nanoscale grain sizes should be related to hardness increase.

关键词： ion beam assisted deposition nanoscale multilayers modulation period modulation ratio deposition temperature hardness

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Diversity and sub-functionalization of TaGW8 homoeologs hold potential for genetic yield improvement in wheat

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The Crop Journal 2019年第6期7卷 830-844页

作者： Lin Ma Chenyang Hao Hongxia Liu Jian Hou Tian Li Xueyong Zhang Key Laboratory of Crop Gene Resources and Germplasm Enhancement Ministry of Agriculture/Institute of Crop SciencesChinese Academy of Agricultural SciencesBeijing 100081China Institute of Animal Sciences Chinese Academy of Agricultural SciencesBeijing 100193China

Grain Weight 8(GW8) in rice is a SQUAMOSA Promoter-Binding Protein-Like(SPL) family transcription factor with multiple biological functions. In this study, three GW8 homoeologs were cloned from homoeologous group 7 chromosomes of wheat. Subcellular localization and trans-activation activity assays suggested that Ta GW8 is a transcriptional activator.Ta GW8 genes were preferentially expressed in young spikes and developing grains. Ectopic expressions of Ta GW8 in Arabidopsis and rice resulted in enhanced vegetative growth,earlier flowering and larger seeds. Ta GW8-7 A was the most highly variable of the three homoeologs with four haplotypes(Hap-1/2/3/4). Ta GW8-7 B had two haplotypes(Hap-L/H).Ta GW8-7 A-Hap-2 was associated with high thousand-grain weight(TGW) and large kernel length and showed higher transcriptional levels and binding activity than the other haplotypes. The high frequency of Ta GW8-7 A-Hap-2 in Chinese wheat populations suggested that it had been extensively selected in breeding. This haplotype showed a high potential for exploitation in global wheat breeding because its frequency was low in exotic germplasm. Ta GW8-7 B-Hap-H produced abundant transcripts and was associated with early heading and maturity, less tiller number and high TGW. This haplotype might be suitable for multiple cropping systems due to short wheat season. In this study we identified sub-functionalization among Ta GW8 homoeologs and obtained functional molecular markers that can be used in breeding for high grain yield.

关键词： Grain yield Haplotype association Marker assisted breeding Thousand grain weight Triticum aestivum

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Isolation and purification of uremic middle molecules by multi-step liquid chromatography

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Science China Chemistry 2002年第3期45卷 225-231页

作者：储结根何炳林刘晓航袁直 State Key Laboratory of Functional Polymer Material for Adsorption and Separation Institute of Polymer Chemistry Nankai University Tianjin China

Isolation and comparison of uremic sera and urine and normal sera and urine were performed by gel permeation chromatography, anion exchange chromatography and re-versed-phase high performance liquid chromatography. Two uremic middle molecular fractions (A and B) were obtained from uremic sera and urine and normal urine by gel permeation chromatography, but not from normal sera. The anion exchange chromatographic results of fraction A from different origins demonstrate that subfraction A-3 could be excreted in urine by healthy subject, but accumulated in uremic serum for renal failure of patient with uremia. After desalinization subfraction A-3 was analyzed by MALDI-TOF-MS. The results show that subfraction A-3 consists of six compounds with molecular weight 839, 873, 1007.94, 1106, 1680 and 2015 respectively. Finally, by reversed-phase high performance liquid chromatography, subfraction A-3 was further resolved into six independent fractions. Thus, the isolation and purification of six middle molecular

关键词： uremic middle molecules reversed-phase high performance liquid chromatography matrix assisted laser desorption/ionization time-of-flight mass spectrometry.

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Simulation of embedded heat exchangers of solar aided ground source heat pump system

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Journal of Central South University 2008年第S2期15卷 261-266页

作者：王芳郑茂余邵俊鹏李忠建 School of Municipal and Environmental Engineering Harbin Institute of Technology Department of Mechanical Power Engineering Harbin University of Science and Technology

Aimed at unbalance of soil temperature field of ground source heat pump system, solar aided energy storage system was established. In solar assisted ground-source heat pump (SAGSHP) system with soil storage, solar energy collected in three seasons was stored in the soil by vertical U type soil exchangers. The heat abstracted by the ground-source heat pump and collected by the solar collector was employed to heating. Some of the soil heat exchangers were used to store solar energy in the soil so as to be used in next winter after this heating period; and the others were used to extract cooling energy directly in the soil by circulation pump for air conditioning in summer. After that solar energy began to be stored in the soil and ended before heating period. Three dimensional dynamic numerical simulations were built for soil and soil heat exchanger through finite element method. Simulation was done in different strata month by month. Variation and restoration of soil temperature were studied. Economy and reliability of long term SAGSHP system were revealed. It can be seen that soil temperature is about 3 ℃ higher than the original one after one year's running. It is beneficial for the system to operate for long period.

关键词： solar assisted ground source heat pump (ASGSHP) soil storage three dimensional simulations heating and cooling

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Recent Advances in Hole Making of FRP/Metal Stacks:A Review

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Transactions of Nanjing University of Aeronautics and Astronautics 2019年第3期36卷 361-375页

作者： CHEN Yan YANG Haojun XU Jiuhua FU Yucan YAN Chaoren Jiangsu Key Laboratory of Precision and Micro-manufacturing Technology College of Mechanical and Electrical EngineeringNanjing University of Aeronautics and Astronautics

Weight reduction is a key driving force for materials development in aerospace industry,which leads to extensive usage of lightweight structural materials such as fiber reinforced polymer(FRP),titanium alloy,aluminum alloy,etc.Hole making is indispensable to assembling these lightweight components by riveted or bolted joints.However,hole making of FRP / metal stacks is always the most challenging task due to differences of material properties between FRP and metals.A comprehensive literature review on hole making of FRP/metal stacks in the last decade is given with a focus on four main aspects including drilling operation,drilling damages and machining parameter optimization,tool performance and wear,and developments in hole making technology.Finally,in order to ensure the precise and efficient hole making of FRP/metal stacks,an idea of low frequency vibration assisted drilling(LFVAD)FRP/metal stacks based on material removal characteristics is put forward by fully exploiting the unique advantages of LFVAD technology.

关键词： fiber reinforced polymer (FRP)/metal stacks drilling machining quality tool wear helical milling vibration assisted drilling abrasive water jet machining

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